Securities

12 Months Ended

Dec. 31, 2024

Investments, Debt and Equity Securities [Abstract]

Securities

Securities

The following tables provide the amortized cost, fair values, and remaining maturities of available for sale debt securities and held to maturity debt securities by security type.

TABLE 51: RECONCILIATION OF AMORTIZED COST TO FAIR VALUE OF DEBT SECURITIES

	DECEMBER 31, 2024
(In Millions)	AMORTIZED COST		GROSS UNREALIZED GAINS		GROSS UNREALIZED LOSSES		FAIR VALUE
Available for Sale Debt Securities
U.S. Government	$	7,388.9	$	1.5	$	22.9	$	7,367.5
Obligations of States and Political Subdivisions	311.2		—		13.6		297.6
Government Sponsored Agency	13,410.5		10.9		132.5		13,288.9
Non-U.S. Government	308.9		0.2		12.3		296.8
Corporate Debt	166.6		0.1		2.9		163.8
Covered Bonds	234.0		0.5		3.6		230.9
Sub-Sovereign, Supranational and Non-U.S. Agency Bonds	4,617.0		8.3		42.2		4,583.1
Other Asset-Backed	2,188.6		7.0		12.9		2,182.7
Commercial Mortgage-Backed	603.4		0.3		13.5		590.2
Total Available for Sale Debt Securities	$	29,229.1	$	28.8	$	256.4	$	29,001.5
Held to Maturity Debt Securities
Obligations of States and Political Subdivisions	$	2,548.2	$	—	$	89.3	$	2,458.9
Government Sponsored Agency	8,635.0		0.9		1,081.3		7,554.6
Non-U.S. Government	3,735.8		0.2		56.3		3,679.7
Corporate Debt	351.6		—		11.0		340.6
Covered Bonds	1,776.8		0.1		62.2		1,714.7
Certificates of Deposit	336.0		—		0.3		335.7
Sub-Sovereign, Supranational and Non-U.S. Agency Bonds	4,146.9		1.4		171.3		3,977.0
Other Asset-Backed	107.1		0.3		0.1		107.3
Commercial Mortgage-Backed	37.6		—		0.8		36.8
Other	621.7		—		172.5		449.2
Total Held to Maturity Debt Securities	$	22,296.7	$	2.9	$	1,645.1	$	20,654.5
Total Debt Securities	$	51,525.8	$	31.7	$	1,901.5	$	49,656.0

	DECEMBER 31, 2023
(In Millions)	AMORTIZED COST		GROSS UNREALIZED GAINS		GROSS UNREALIZED LOSSES		FAIR VALUE
Available for Sale Debt Securities
U.S. Government	$	3,681.5	$	2.2	$	61.5	$	3,622.2
Obligations of States and Political Subdivisions	315.8		—		20.0		295.8
Government Sponsored Agency	11,744.3		9.0		200.3		11,553.0
Non-U.S. Government	284.8		—		20.4		264.4
Corporate Debt	287.5		0.1		8.1		279.5
Covered Bonds	356.8		—		9.7		347.1
Sub-Sovereign, Supranational and Non-U.S. Agency Bonds	3,013.8		0.1		114.0		2,899.9
Other Asset-Backed	3,061.0		1.6		100.0		2,962.6
Commercial Mortgage-Backed	913.5		0.2		48.4		865.3
Total Available for Sale Debt Securities	$	23,659.0	$	13.2	$	582.4	$	23,089.8
Held to Maturity Debt Securities
Obligations of States and Political Subdivisions	$	2,563.9	$	0.5	$	72.4	$	2,492.0
Government Sponsored Agency	9,355.3		2.3		1,012.4		8,345.2
Non-U.S. Government	4,789.1		0.2		90.7		4,698.6
Corporate Debt	646.1		—		28.2		617.9
Covered Bonds	2,208.6		0.3		108.3		2,100.6
Certificates of Deposit	585.1		—		0.7		584.4
Sub-Sovereign, Supranational and Non-U.S. Agency Bonds	5,245.5		3.2		294.9		4,953.8
Other Asset-Backed	214.2		0.4		0.2		214.4
Commercial Mortgage-Backed	37.6		—		0.8		36.8
Other	576.3		—		147.0		429.3
Total Held to Maturity Debt Securities	$	26,221.7	$	6.9	$	1,755.6	$	24,473.0
Total Debt Securities	$	49,880.7	$	20.1	$	2,338.0	$	47,562.8

TABLE 52: REMAINING MATURITY OF DEBT SECURITIES

DECEMBER 31, 2024	ONE YEAR OR LESS				ONE TO FIVE YEARS				FIVE TO TEN YEARS				OVER TEN YEARS				TOTAL
(In Millions)	Amortized Cost		Fair Value		Amortized Cost		Fair Value		Amortized Cost		Fair Value		Amortized Cost		Fair Value		Amortized Cost		Fair Value
Available for Sale Debt Securities
U.S. Government	$	397.4	$	396.2	$	5,326.2	$	5,309.3	$	1,665.3	$	1,662.0	$	—	$	—	$	7,388.9	$	7,367.5
Obligations of States and Political Subdivisions	—		—		242.5		232.0		68.7		65.6		—		—		311.2		297.6
Government Sponsored Agency	3,087.3		3,065.5		7,129.2		7,077.9		2,389.5		2,362.9		804.5		782.6		13,410.5		13,288.9
Non-U.S. Government	—		—		308.9		296.8		—		—		—		—		308.9		296.8
Corporate Debt	126.4		124.9		40.2		38.9		—		—		—		—		166.6		163.8
Covered Bonds	—		—		234.0		230.9		—		—		—		—		234.0		230.9
Sub-Sovereign, Supranational and Non-U.S. Agency Bonds	171.2		169.6		4,152.0		4,129.9		293.8		283.6		—		—		4,617.0		4,583.1
Other Asset-Backed	50.4		49.7		1,561.5		1,552.7		471.2		474.1		105.5		106.2		2,188.6		2,182.7
Commercial Mortgage-Backed	45.1		44.8		524.6		518.6		33.7		26.8		—		—		603.4		590.2
Total Available for Sale Debt Securities	$	3,877.8	$	3,850.7	$	19,519.1	$	19,387.0	$	4,922.2	$	4,875.0	$	910.0	$	888.8	$	29,229.1	$	29,001.5
Held to Maturity Debt Securities
Obligations of States and Political Subdivisions	$	115.3	$	114.7	$	1,387.7	$	1,357.2	$	892.9	$	845.8	$	152.3	$	141.2	$	2,548.2	$	2,458.9
Government Sponsored Agency	888.5		793.6		3,358.8		2,971.4		2,771.9		2,426.5		1,615.8		1,363.1		8,635.0		7,554.6
Non-U.S. Government	2,697.3		2,696.6		1,038.5		983.1		—		—		—		—		3,735.8		3,679.7
Corporate Debt	142.3		140.4		194.7		187.5		14.6		12.7		—		—		351.6		340.6
Covered Bonds	475.3		473.8		1,178.7		1,123.8		122.8		117.1		—		—		1,776.8		1,714.7
Certificates of Deposit	336.0		335.7		—		—		—		—		—		—		336.0		335.7
Sub-Sovereign, Supranational and Non-U.S. Agency Bonds	2,126.2		2,075.0		2,015.4		1,897.5		5.3		4.5		—		—		4,146.9		3,977.0
Other Asset-Backed	—		—		77.8		78.1		29.3		29.2		—		—		107.1		107.3
Commercial Mortgage-Backed	—		—		37.6		36.8		—		—		—		—		37.6		36.8
Other	61.4		60.1		327.8		295.1		50.4		38.6		182.1		55.4		621.7		449.2
Total Held to Maturity Debt Securities	$	6,842.3	$	6,689.9	$	9,617.0	$	8,930.5	$	3,887.2	$	3,474.4	$	1,950.2	$	1,559.7	$	22,296.7	$	20,654.5
Total Debt Securities	$	10,720.1	$	10,540.6	$	29,136.1	$	28,317.5	$	8,809.4	$	8,349.4	$	2,860.2	$	2,448.5	$	51,525.8	$	49,656.0

Note: Mortgage-backed and asset-backed securities are included in the above table taking into account anticipated future prepayments.

Credit Quality. AFS debt securities impairment reviews are conducted quarterly to identify and evaluate securities that have indications of possible credit losses. A determination as to whether a security’s decline in market value is related to credit impairment takes into consideration numerous factors and the relative significance of any single factor can vary by security. Factors Northern Trust considers in determining whether impairment is credit-related include, but are not limited to, the severity of the impairment; the cause of the impairment; the financial condition and near-term prospects of the issuer; activity in the market of the issuer, which may indicate adverse credit conditions; Northern Trust’s intent regarding the sale of the security as of the balance sheet date; and the likelihood that Northern Trust will not be required to sell the security for a period of time sufficient to allow for the recovery of the security’s amortized cost basis. For each security meeting the requirements of Northern Trust’s internal screening process, an extensive review is conducted to determine if a credit loss has occurred.

There was a $0.2 million allowance for credit losses for AFS securities for the year ended December 31, 2024, reflecting a $1.0 million release from December 31, 2023. There was a $1.2 million allowance for credit losses for AFS securities for the year ended December 31, 2023, reflecting a $0.1 million release from December 31, 2022. The process for identifying credit losses for AFS securities is based on the best estimate of cash flows to be collected from the security, discounted using the security’s effective interest rate. If the present value of the expected cash flows is found to be less than the current amortized cost of the security, an allowance for credit losses is generally recorded equal to the difference between the two amounts, limited to the amount the amortized cost basis exceeds the fair value of the security. For additional information, please refer to Note 6, “Allowance for Credit Losses.”

The following table provides information regarding AFS debt securities with no credit losses reported that had been in a continuous unrealized loss position for less than twelve months and for twelve months or longer as of December 31, 2024 and 2023.

TABLE 53: AVAILABLE FOR SALE DEBT SECURITIES IN UNREALIZED LOSS POSITION WITH NO CREDIT LOSSES REPORTED

AS OF DECEMBER 31, 2024	LESS THAN 12 MONTHS				12 MONTHS OR LONGER				TOTAL
(In Millions)	FAIR VALUE		UNREALIZED LOSSES		FAIR VALUE		UNREALIZED LOSSES		FAIR VALUE		UNREALIZED LOSSES
U.S. Government	$	4,477.5	$	11.1	$	532.3	$	11.8	$	5,009.8	$	22.9
Obligations of States and Political Subdivisions	—		—		297.5		13.6		297.5		13.6
Government Sponsored Agency	3,298.8		14.5		6,373.8		118.0		9,672.6		132.5
Non-U.S. Government	54.9		0.1		181.6		12.2		236.5		12.3
Corporate Debt	—		—		76.9		1.6		76.9		1.6
Covered Bonds	—		—		119.6		3.6		119.6		3.6
Sub-Sovereign, Supranational and Non-U.S. Agency Bonds	881.9		2.6		720.5		39.6		1,602.4		42.2
Other Asset-Backed	35.4		—		405.4		12.9		440.8		12.9
Commercial Mortgage-Backed	—		—		376.1		13.5		376.1		13.5
Total	$	8,748.5	$	28.3	$	9,083.7	$	226.8	$	17,832.2	$	255.1

Note: One corporate debt AFS security with a fair value of $38.9 million and unrealized loss of $1.3 million has been excluded from the table above as it has a $0.2 million allowance for credit losses reported as of December 31, 2024. Refer to the discussion further above and Note 6, “Allowance for Credit Losses” for further information.

AS OF DECEMBER 31, 2023	LESS THAN 12 MONTHS				12 MONTHS OR LONGER				TOTAL
(In Millions)	FAIR VALUE		UNREALIZED LOSSES		FAIR VALUE		UNREALIZED LOSSES		FAIR VALUE		UNREALIZED LOSSES
U.S. Government	$	—	$	—	$	3,364.7	$	61.5	$	3,364.7	$	61.5
Obligations of States and Political Subdivisions	87.8		5.9		208.0		14.1		295.8		20.0
Government Sponsored Agency	331.0		11.5		9,486.6		188.8		9,817.6		200.3
Non-U.S. Government	—		—		264.5		20.4		264.5		20.4
Corporate Debt	4.4		0.1		143.0		2.1		147.4		2.2
Covered Bonds	—		—		213.2		9.7		213.2		9.7
Sub-Sovereign, Supranational and Non-U.S. Agency Bonds	—		—		2,477.0		105.8		2,477.0		105.8
Other Asset-Backed	19.8		2.0		1,998.7		98.0		2,018.5		100.0
Commercial Mortgage-Backed	60.0		4.6		776.6		43.8		836.6		48.4
Total	$	503.0	$	24.1	$	18,932.3	$	544.2	$	19,435.3	$	568.3

Note: Three corporate debt AFS securities with a fair value of $98.4 million and unrealized losses of $5.9 million and one sub-sovereign, supranational and non-U.S. agency bonds AFS security with a fair value of $71.0 million and unrealized loss of $8.2 million have been excluded from the table above as these AFS securities have a $1.2 million allowance for credit losses reported as of December 31, 2023. Refer to the discussion further above and Note 6, “Allowance for Credit Losses” for further information.

As of December 31, 2024, there were 767 AFS debt securities with a combined fair value of $17.8 billion in an unrealized loss position without an allowance for credit losses, with their unrealized losses totaling $255.1 million. As of December 31, 2023, there were 898 AFS debt securities with a combined fair value of $19.4 billion in an unrealized loss position without an allowance for credit losses, with their unrealized losses totaling $568.3 million. Unrealized losses on AFS debt securities without an allowance for credit losses are primarily attributable to changes in market interest rates and credit spreads since their purchase.

The following table provides the amortized cost of HTM debt securities by credit rating using ratings from Moody’s, S&P Global or Fitch Ratings. Securities not explicitly rated were grouped where possible under the credit rating of the issuer of the security.

TABLE 54: AMORTIZED COST OF HELD TO MATURITY DEBT SECURITIES BY CREDIT RATING

	AS OF DECEMBER 31, 2024
($ In Millions)	AAA			AA			A			BBB			NOT RATED			TOTAL
Obligations of States and Political Subdivisions	$	1,024.3		$	1,523.9		$	—		$	—		$	—		$	2,548.2
Government Sponsored Agency	8,635.0			—			—			—			—			8,635.0
Non-U.S. Government	700.0			704.2			2,020.1			311.5			—			3,735.8
Corporate Debt	—			191.5			160.1			—			—			351.6
Covered Bonds	1,776.8			—			—			—			—			1,776.8
Certificates of Deposit	316.6			—			—			—			19.4			336.0
Sub-Sovereign, Supranational and Non-U.S. Agency Bonds	3,132.8			984.5			28.5			1.1			—			4,146.9
Other Asset-Backed	107.1			—			—			—			—			107.1
Commercial Mortgage-Backed	37.6			—			—			—			—			37.6
Other	50.7			—			—			—			571.0			621.7
Total	$	15,780.9		$	3,404.1		$	2,208.7		$	312.6		$	590.4		$	22,296.7
Percent of Total	71		%	15		%	10		%	1		%	3		%	100		%

	AS OF DECEMBER 31, 2023
($ In Millions)	AAA			AA			A			BBB			NOT RATED			TOTAL
Obligations of States and Political Subdivisions	$	954.7		$	1,609.0		$	—		$	—		$	0.2		$	2,563.9
Government Sponsored Agency	9,355.3			—			—			—			—			9,355.3
Non-U.S. Government	813.3			1,179.6			2,463.3			332.9			—			4,789.1
Corporate Debt	2.1			302.6			341.4			—			—			646.1
Covered Bonds	2,208.6			—			—			—			—			2,208.6
Certificates of Deposit	545.9			—			—			—			39.2			585.1
Sub-Sovereign, Supranational and Non-U.S. Agency Bonds	4,047.9			1,166.5			30.0			1.1			—			5,245.5
Other Asset-Backed	214.2			—			—			—			—			214.2
Commercial Mortgage-Backed	37.6			—			—			—			—			37.6
Other	54.8			—			—			—			521.5			576.3
Total	$	18,234.4		$	4,257.7		$	2,834.7		$	334.0		$	560.9		$	26,221.7
Percent of Total	70		%	16		%	11		%	1		%	2		%	100		%

Credit quality indicators are metrics that provide information regarding the relative credit risk of debt securities. Northern Trust maintains a high quality debt securities portfolio, with 96% and 97% of the HTM portfolio at December 31, 2024 and December 31, 2023, respectively, comprised of securities rated A or higher.

Investment Security Gains and Losses. Proceeds of $2.0 billion, $5.2 billion and $138.7 million in 2024, 2023 and 2022, respectively, from the sale of debt securities resulted in the pre-tax Investment Security Gains (Losses), net shown in the following tables.

TABLE 55: INVESTMENT SECURITY GAINS AND LOSSES

	DECEMBER 31,
(In Millions)	2024		2023		2022
Gross Realized Debt Securities Gains	$	185.2	$	10.5	$	—
Gross Realized Debt Securities Losses	(374.5)		(180.0)		(214.0)
Investment Security Gains (Losses), net(1)	$	(189.3)	$	(169.5)	$	(214.0)

(1) $214.0 million of Investment Security Losses for the year ended December 31, 2022, includes a $213.0 million loss recognized in 2022 in conjunction with the intent to sell certain AFS debt securities.

TABLE 56: INVESTMENT SECURITY GAINS AND LOSSES BY SECURITY TYPE

	DECEMBER 31,
(In Millions)	2024		2023		2022
U.S. Governments	$	(34.8)	$	(29.9)	$	—
Obligations of States and Political Subdivisions	—		9.8		(95.8)
Government Sponsored Agency	(23.0)		(73.2)		—
Corporate Debt	—		(7.6)		(67.3)
Covered Bonds	(4.2)		—		—
Sub-Sovereign, Supranational and Non-U.S. Agency Bonds	(48.2)		(9.1)		—
Other Asset-Backed	(56.5)		(58.6)		(17.1)
Commercial Mortgage-Backed	(22.6)		(0.9)		(33.8)
Investment Security Gains (Losses), net(1)	$	(189.3)	$	(169.5)	$	(214.0)

(1) $214.0 million of Investment Security Losses for the year ended December 31, 2022, includes a $213.0 million loss recognized in 2022 in conjunction with the intent to sell certain AFS debt securities.